ABSTRACT Illicit substance use and related problems such as HIV-risk behavior among adolescents has been persistently high over the past decade and remains one of the most pressing public health concerns in the United States. Although a number of evidence-based treatments are now available for adolescent substance abuse the potential impact of these treatments is dramatically undercut by the limited number of adolescents with substance use disorders who actually receive them. More than 90% of the estimated 2.6 million adolescents with substance abuse or dependence go untreated each year pointing to a serious treatment gap in adolescent health care. Nationwide, the juvenile justice system, which includes a disproportionately high number of minority youth, is the primary avenue for adolescents gaining entry into the treatment system. Intervening with adolescents referred to juvenile justice for their first drug-related offense represents a vital opportunity for early intervention that could prevent the trajectory of escalating substance use and sexually transmitted infections such as HIV for which these youth are at risk, thereby providing significant benefits to youth, their families and society. Intervention following their first offense is especially important in light of evidence that the average time between first illicit substance use and a pattern of regular use is 2.5 months. The proposed research represents a collaborative effort between investigators at the Oregon Research Institute (ORI) and the juvenile justice divisions of Multnomah and Washington counties in Portland, Oregon that vary in urban-rural and minority distributions. The project is designed to evaluate two brief, sustainable interventions for a sample of 280 adolescents charged with an initial drug-related offense: Motivational Enhancement Therapy (MET) intervention for youth and the Parenting Wisely intervention for parents. Both MET and PW are developmentally appropriate and theoretically grounded evidence-based interventions that hold promise as early treatments for substance-involved adolescents. The study will evaluate MET and PW in a design involving the randomization of families to one of four intervention conditions; youth will receive either MET or a drug education (EDUC) intervention and parents receive either PW or a parent notification letter; the letter serves as a platform intervention that all families receive. Families will be assessed for adolescent substance use and HIV-risk, recidivist substance-related offenses, treatment entry, and other areas of parent and adolescent functioning at baseline, 3-month, and 6-month assessments. Study findings will have important treatment services and public health implications for establishing MET and PW as easily accessible, cost-effective, and cost-efficient interventions that could be easily transported to and sustained in juvenile justice settings.